Coating material containing perfluore poly ether structure

ABSTRACT

The invention relates to a coating material comprising condensates of at least one compound (A) of the general formula R a MZ b  (a=0-3; b=1-4; a+b=3, 4), where R is a non-hydrolyzable organic group, and at least one compound (B) of the general formula R′xMZ y (x=1-3; y=1-3; x+y=3, 4), where R is a non-hydrolyzable organic group and at least one R′ contains a perfluoro polyether structure separated from M by at least two atoms, where M is an element from the periodic table of elements selected from the main groups III-V or from the subgroups II-IV and Z is a hydrolyzable organic group, and where at least one R is not equal to at least one R′.

FIELD OF THE INVENTION

The invention concerns a coating material based on modifiedpolysilsesquioxanes (highly crosslinked materials, for example, with theempirical formula RSiO_(1.5)), their synthesis and use of the coatingmaterial to coat surfaces, especially porous polymers, to achieveoleophobic properties with high temperature stability. The inventionalso concerns a material coated with this coating material and itsapplications, as well as an aeration and deaeration element.

BACKGROUND OF THE INVENTION

Polymer surfaces typically have hydrophobic, but not oleophobic,properties and are wettable for liquids with low surface tension(solvents). Even microporous polytetrafluoroethylene (PTFE) with knownhigh hydrophobic and oleophobic properties is wettable by liquids withsurface tensions <28 mN/m (cf. EP 0,581,168).

Numerous fluorine-containing coating compositions for oleophobizing ofpolymer or porous surfaces are already known, which, however, leave roomfor improvement, especially in degree of olephobism, temperaturestability and oleophobism at elevated temperature.

Coatings based on fluorinated alkyl (meth)acrylates for coating ofpolyolefins (PP,PE) are described in EP 0,581,168 (Mitsubishi).

Oleophobic coating of microporous (ePTFE) Teflon AF is described in EP0,561,875.

WO 92/21715 describes the use of perfluoropolyether as oil-repellentcoating for microporous polymers. Silicon alkoxides withperfluoropolyether side chains for dirt-repellent coating of siliconesurfaces are described in Japanese Application JP 4-213384.

Coating materials based on mixtures of alkoxysilanes, alkoxysilanes withorganic nonhydrolyzable side groups and silanes with perfluorinated sidegroups, which carry perfluorinated groups enriched on the air surfaceafter crosslinking, are described in EP 0 587 667. R. Kasemann et al.,New J. Chem., 1994, 18 page 1117, describes such functional coatingsproduced via the sol-gel process.

Only a method for production of a gel from an inorganic oxide is knowfrom WO 97/01508, in which at least one fluorinated inorganic oxideprecursor is mixed with a fluorinated acid. Addition of a fluorinatedsolvent is absolutely essential. These are cost-intensive andenvironmentally relevant. It is also disclosed that a layer of materialproduced in this way is used as an “adhesion aid” for a fluoropolymerlayer. Possible use of the coating for oleophobization is not described.WO 97/01599 describes a composition from a fluoropolymer and aninorganic oxide produced as described in WO 97/01508.

The task according to the invention consists of preparing a coatingmaterial having high oleophobism.

Another task is to apply a coating material to substrate surfaces,especially porous polymers, in which the coated substrate exhibits higholeophobism.

Another task is to produce a coated substrate with high oleophobism,having high temperature stability.

A further task is to produce a coated substrate, in which only a slightchange in permeability of the substrate develops from the coating or theporosity is essentially uninfluenced, in the case of porous substrates.

A next task is to produce such a coating material without having to useenvironmentally relevant, especially fluorinated, solvents.

A last task is to devise an aeration and deaeration element that hasversatile use and prevents entry or passage of liquids.

SUMMARY OF THE INVENTION

The coating material according to the invention comprises condensates ofat least one compound A with general formula R_(a)MZ_(b) (a=0-3; b=1-4;a+b=3-4), in which R is a nonhydrolyzable organic group, and at leastone compound B of the general formula R′_(x)MZ_(y) (x=1-3; y=1-3;x+y=3-4), in which R′ is a nonhydrolyzable organic group and at leastone R′ contains a perfluoropolyether structure separated from M by atleast two atoms, in which M is an element chosen from groups IIIA-VA orgroups IIB-IVB of the periodic system and Z is a hydrolyzable organicgroup, and in which at least one R is not identical to at least one R′.

The coating material according to the invention can be applied to a 35substrate. In a preferred variant the substrate is a porous polymer,especially a textile fabric or a fluoropolymer or fluoropolymer blend,especially in microporous form, like expanded polytetrafluoroethylene(ePTFE).

The invention also offers a process for production of a coatingmaterial, in which at least one compound A of the general formulaR_(a)MZ_(b) (a=0-3; b=1-4; a+b=3-4), in which R is a nonhydrolyzableorganic group, and at least one compound B of the general formulaR′_(x)MZ_(y)(x=1-3; y=1-3;x+y=3-4), in which R′ is a nonhydrolyzableorganic group, and at least one R′ contains a perfluoropolyetherstructure separated from M by at least two atoms, in which M is anelement chosen from groups IIIA-VA or groups IIB-IVB of the periodicsystem and Z is a hydrolyzable organic group, and in which at least oneR is not identical to at least one R′, are mixed.

The invention also makes available a process for coating of a substrate,in which a coating material according to the invention is applied to asubstrate and cured. The present invention also creates an aeration anddeaeration element that comprises a coated material, having a substrateand a coating material applied to at least one surface of the substrate,in which the coating material contains condensates of a least onecompound A of general formula R_(a)MZ_(b) (a=0-3; b=1-4; a+b=3,4), inwhich R is a nonhydrolyzable organic group, and at least one compound Bof the general formula R′_(x)MZ_(y) (x=1-3; y=1-3; x+y=3,4), in which R′is a nonhydrolyzable organic group, and at least one R′ contains aperfluoropolyether structure separated from M by at least two atoms, inwhich M is an element chosen from groups IIIA-VA or groups IIB-IVB ofthe periodic system and Z is a hydrolyzable organic group, and in whichat least one R is not identical to at least one R′.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic section of an aeration and deaeration elementin the form of a screw;

FIG. 2 shows a schematic section of an aeration and deaeration elementin the form of a screw with cover; and

FIG. 3 shows a section through the coated material 13 in an aeration anddeaeration element according to the invention.

DETAILED DESCRIPTION

“Condensate” means an oligomer or polymer possessing at least onemetal-oxygen metal bond, which usually forms by condensation of two OHgroups bonded to metal atoms.

A “nonhydrolyzable organic group” is understood to mean any organicgroup bonded to a metal atom, in which no hydrolytic cleavage of thebond between the metal and organic group occurs in the reaction medium(for example, Si—C bond).

A “hydrolyzable group” is any group bonded to a metal atom M, which anform M—O—H groups by reaction with water, optionally catalyzed by acidsor bases.

A “perfluoropolyether structure” means a polyfluoroxyalkylene group, inwhich poly- or perfluorinated groups are generally bonded via at leastone oxygen bridge.

A “membrane” is a porous film, according to this application.

“Porous” denotes a structure having joined pores or cavities, which areconfigured so that continuous passages or paths through the material areformed.

“Surface” of the substrate means both the outer and inner surface, ifpresent. Inner surface means the walls of the pores of cavities of aporous substrate.

The inventors found, for the first time, that coating materials thatsolve the task of the invention can be made accessible by hydrolysis andcondensation of a mixture of at least two compounds, namely, at leastone metal compound with hydrolyzable groups, and at least one metalcompound with at least one nonhydrolyzable organic group, in which atleast one nonhydrolyzable group must contain a perfluoropolyetherstructure.

Such coatings are characterized by very high oleophobism. Oil values ofthe coating and the coated substrate of >3, especially >5 andpreferably >7, can then be achieved. The very high oleophobism can beexplained by the fact that the perfluoropolyether chains enriched on thelayer surface are extremely ordered (for example, crystalline), owing tothe effect of the underlying matrix formed from highly crosslinkedpolycondensates.

It is important that at least two of the mentioned compounds, i.e., acompound A and a compound B, are present. If only one compound ischosen, these high oil values cannot be achieved.

The oil values of the coated substrate are also dependent on the surfaceporosity of the substrate.

The coatings also exhibit high oleophobism at high temperatures and aretemperature-resistant. Thus, the oil value of the coated substrate,after heat treatment at 160° C., lasts for 12 hours, at 200° C. for 2hours and especially at 250° C. for 2 hours. Transmission fluid (ATFOil, Autran DXII, BP Hamburg) does not wet the structure for 12 hours,up to 200° C. This means, in particular, that the wetting angle of adrop of transmission fluid on the coating and subsequent heat treatmentat 160° C. for 12 hours is ≧10°.

Preferred examples of the metal atom M are Al, B, Ge, Sn, Ti, Zr andespecially Si.

Examples of hydrolyzable groups Z in the educts (monomeric compounds oralso oligomeric or polymeric precondensates, optionally with different Matoms) are halogens and especially OR″groups, in which R″ is an organicgroup, for example, alkyl groups, especially with 1-5 carbon atoms(methyl, ethyl, etc.), carbonyl-functionalized groups, like C═OCH₃ orC═OCH₂CH₃, aryl compounds, like phenyl, alkoxy-functionalized alkanes,like alkylmethoxy or alkylethoxy compounds. Organic groups R″ that formalcohols with boiling points <200° C., especially <100° C. duringhydrolysis, are particularly preferred, since removal of the volatilehydrolysis products is possible in simple fashion because of this.Instead of hydrolyzable OR″ groups, other groups can also be used (forexample, halogen), which form MOH groups by hydrolysis. Such groups,however, are not particularly preferred, since the hydrolysis productsformed in parallel (acids, salts) generally cannot be removed simplyfrom the layer.

Examples of nonhydrolyzable groups R or R′, in which one or moredifferent R or R′ can be bonded to metal-atom M, are the followingnonfluorine containing groups: alkenyl (especially C₂-C₄ alkenyl),alkynyl (C₂-C₄), acryl, methacryl, aryl (especially C₆-C₁₀) andespecially alkyl groups C₁-C₅, for example, methyl, ethyl, propyl,isopropyl).

Oligomeric or polymeric precondensates, optionally with different Matoms and R or R′ groups, can also be used, in addition to monomericcompounds of the general formula R_(aMZ) _(b) or R′_(x)MZ_(y).

Examples of fluorine-containing, nonhydrolyzable groups R, R′ arecompounds carrying a perfluoropolyether side chain with the generalformula:

(R_(p)-X-)_(a)MR_(mb)Z_(ci) (a+b+c=3, 4; a=1-3; b=0, 1,2), in whichR_(m) is a nonhydrolyzable organic group. M═Si and/or Z═OR″ isparticularly preferred.

R_(p) stands for a perfluoropolyether structure, for example,CF₃CF₂CF₂[OCF(CF₃)CF₂]_(x)OCF(CF₃)(CF₂CF₂)_(y)—(x and y ≧0, preferablyx=1-10) or CF₃[OCF(CF₃)CF₂]_(d)(OCF₂)_(e)—(d and e ≧0, preferablyd=1-10).

The perfluoropolyether structure then contains preferably 6-100 fluorineatoms.

X describes a group that separates Rp from Si by at least two atoms, forexample,

—CH₂COOCH₂CH(OH)CH₂, COO, SO₂NH, CONH, COOCH₂CH(OH)(CH₂)_(z)(z=2-4).

(z=2-4), COO(CH₂), (z=2-4),

SO₂NH(CH₂)(z=2-4), CONH—(CH₂)_(z)(z=2-4).

Examples of hydrolyzable groups Z and nonhydrolyzable groups R_(m) forcomponents carrying R_(p) groups are identical to those described abovefor RMZ or R′MZ compounds.

A preferred compound A is Si(OR″)₄, a particularly preferred compound Ais RSi(OR″)₃, in which R is a nonhydrolyzable organic group and R″ is aC₁-C₅ alkyl.

In compound B a preferred compound is R′Si(OR)₃, in which R′ is anonhydrolyzable organic group. A particularly preferred compound Bconsists of CF₃[OCF(CF₃)CF₂]_(d)(OCF₂)_(e)OCONHCH₂CH₂CH₂Si(OR)₃ (d ande >0, preferably d=1-10).

The molar ratio of the groups R:R′ especially lies between 0.1:100 and100:0.1.

Suspensions of metal oxide particles, for example, the elements Ti, Zr,Al, Si, can also be added as additional components. Particle sizes of <1μm are preferred, especially <100 nm (for example, silica sols (SiO₂) ofthe Bayer Company). Such components are incorporated into the inorganicnetwork via the surface OH groups by condensation reactions and canimprove the mechanical properties of the layers.

The coating material is preferably produced by the sol-gel process. Thesol-gel process is defined as a process in which colloidally disperseddissolved particles (sols) are produced by condensation, starting frommolecules that carry hydrolyzable groups. The condensation reactions insuch sols generally do not run completely. Sols are liquid intermediatesthat can be used as a coating material. After the coating step andcomplete buildup of the structure formed by condensation, in whichadditional crosslinking mechanisms can optionally be used (for example,polymerization of organic functional groups), the pores present in thestructure at this point are filled with solvents (gel). After thesolvent is driven off (for example, by heat, vacuum), the material thatremains as coating on the substrate is formed.

The aforementioned educts are therefore mixed and hydrolyzed to producethe coating composition. In the simplest case, hydrolysis of the mixturecan occur at ambient temperature and pressure without addition offurther additives and without additional physical treatment.

However, water is preferably added to the educts (preferably >0.5 molper mol of Z groups) or relatively limited amounts of acids or bases forcatalysis. The preferred concentration of acids and/or bases is >0.1mmol per liter of mixture, especially >0.1 mmol and <10 mol per liter ofmixture. Examples are inorganic or organic acids or bases, especiallyammonia, alkali and alkaline earth hydroxides (NaOH, KOH), amines,formic acid, acetic acid, propionic acid, hydrochloric acid, sulfuricacid, phosphoric acid. Volatile compounds that can easily be driven outfrom the layer, for example, during the thermally induced curing step,are particularly preferred. Catalyst mixtures can also be used, in whichthe total catalyst concentration can be up to 10 mol per liter.Agitation is preferred during synthesis, optionally to application ofthe coating. It is possible to cool the mixture to reduce the reactionrate.

It is generally advantageous, departing from the ordinary state of theart, to conduct hydrolysis in steps, in which the components notcarrying R_(p) groups are prehydrolyzed in one or more steps, forexample, by addition of water, and the components carrying the R_(p)groups are added in the subsequent step. If hydrolysis of the mixture ofall components is run in one step, phase separations in the coatingcomposition are frequently observed, which can lead to nonhomogeneouslayers.

Appropriate, preferably nonenvironmentally relevant solvents (forexample, mono- or polyfunctionalized alcohols (C₁-₁₀), especiallyvolatile alcohols, like methanol, ethanol, propanol, isopropanol) can beadded after or during the hydrolysis step to adjust the appropriatesolids content (preferably 0.1-50 wt. %).

When inorganic acids are used as catalysts during synthesis, ionexchangers can be used, in particular, after individual hydrolysis stepsor at the end of synthesis, in order to separate ions that can lead toreduction of chemical stability or pot life. In this case, the ionexchanger is ordinarily added in solid form and then separated byfiltration. Examples of applicable ion exchangers are anion exchangersor cation exchangers, for example, Dowex 50 W×2, Amberlyst A-21 (FlukaChemie AG Switzerland).

If water is to used as solvent after the hydrolysis or partialcondensation steps, most of the formed volatile components can beseparated, for example, by distillation. Water is then added, in which asuspension is formed, to which surfactants can then optionally be addedto reduce the surface tension or for improved wetting. A homogeneouscoating, even on the inner surface of the substrate, is made possible bywetting of a microporous substrate.

Essentially all materials can be used as substrate for coating, forexample, metal, glass or polymers, especially porous polymers. Polymersappropriate as substrate include fluoropolymers, likepolytetrafluoroethylene (PTFE), especially expanded PTFE (ePTFE),microporous stretched PTFE, as described in U.S. Pat. Nos. 3,953,556 and4,187,390; stretched PTFE provided with hydrophilic impregnation agentsand/or layers, as described in U.S. Pat. No. 4,194,041; polyolefins,like polyethylene or polypropylene; polyamides; polyesters;polycarbonates; polyurethanes; elastomers, like copolyether-esters; andsimilar compounds, as well as polymer blends.

The substrate can be present in different forms, for example, asmembranes or film, as a sealant or as a textile fabric. Textile fabricsare generally understood to mean meshes, knits, wovens or nonwovens. Thesubstrate can also be a laminate, in which at least one layer is formedfrom a membrane or film and at least one layer consists of a textilefabric. The layers can be joined to each other, for example, in the formof gluing, sealing or lamination. If the substrate is present in theform of a laminate or a film, this can also be bonded to a textilefabric after treatment with the coating.

Homogeneous, thin coatings are obtained after application of the coatingmaterial by ordinary coating techniques onto the surface of thesubstrate and preferably heat-induced crosslinking and driving off ofthe volatile components (water, alcohols formed or added duringhydrolysis). In the case of porous structures, a homogeneous, very thin(in the nanometer to micrometer range) coating of the inner surface mustbe achieved, so as not to significantly reduce the porosity or poresize, i.e., for example, to avoid film formation or filling of thepores, which would lead to a significant reduction in permeability. Thethickness of the coating is then naturally dependent on the applicationamount, i.e., a reduction of permeability is generally observed withincreasing application amount. The permeability is preferably onlyslightly influenced by the coating, i.e. the permeability is reduced, atmost, 40%, preferably, at most, 20% in comparison with the uncoatedsubstrate.

To produce polar surface groups on the substrate, especially OH groups,the substrate can be pretreated, for example, by corona or plasmapretreatment, in order to permit chemical bonding of the coatingmaterial by condensation of the surface OH groups with OH groups of thesol components.

All known coating methods for application of liquid media can be used,for example, spraying, dipping, doctoring, screen printing, especiallyroll coating techniques. The concentration, solids content of thesolution and/or pressure or temperature can then be varied. Adjustmentof the solids content of the coating material and thus regulation of thethickness of the coating in the process according to the invention ispossible, for example, by varying the added amount of solvent (forexample, isopropanol, ethanol) during or after synthesis.

The coated substrate can be cured in conjunction with the coating step.This can occur, for example, by heat treatment, IR radiation or vacuum.For example, the coating can be cured for 0.1-60 minutes at 50° C.-250°C., preferably 120° C.-180° C. This type of treatment can also beconducted to evaporate the solvent.

The coated material according to the invention, which can have a poroussubstrate, for example, in the form of films, membranes or laminates,can find numerous applications because of the high permeability,temperature resistance and oleophobism, for example, as a filter medium.This coated material according to the invention is also particularlysuited for use in aeration and deaeration elements, since the coatedmaterial can simultaneously prevent entry and passage of liquid mediabecause of its properties. Examples of such applications includepressure equalization elements for electronic housings, sensors, lights,liquid containers, especially in technical or automotive applications.

The coating material according to the invention can serve in nonporoussubstrates as an antisoiling or antiadhesion agent because of itsproperties.

The aeration and deaeration element according to the invention, whichincorporates a material coated according to the invention as described,is generally designed in the form so that an opening of the containerbeing aerated and deaerated is covered with a substrate coated accordingto the invention. Joining of the substrate coated according to theinvention (membrane, laminate) with the edge of the opening of thecontainer can occur in any form or joining technique that permitsliquid-tight joining. Examples of joining techniques include clamping,gluing, injection molding. The coated substrate according to theinvention is preferably joined to the edge of the opening of thecontainer being aerated and deaerated by means of a selfadhesive film.Another preferred variant preferably has a frame that possesses at leastone air inlet and outlet opening, and the air inlet and outlet openingis covered by the coated material. The frame has the function ofpermitting a simple joining technique to the container being aerated anddeaerated, for example, screwing, locking of snapon closures, etc.

The shape and material of the frame that carries the coated material oris joined to this material can be varied in numerous ways.

Depending on the area of application, the frame can consist of metal,ceramic, plastic (especially polypropylene [PP] or polyethylene [PE]).

The shape and size of the frame depends on the recess or opening of thecontainer being aerated or deaerated in which the element is to be used.The frame of the aeration and deaeration element according to theinvention can have the shape of a ring or sleeve. The aeration anddeaeration element according to the invention preferably has the shapeof a screw with an axial through-hole, in which the through-hole iscompletely covered with the coated material in the region of the screwhead.

The coated material can be joined to the frame in different ways. Forexample, in a two-part frame consisting of two rings it can be attachedbetween these rings by clamping. The coated material is preferably gluedto the frame. In this case, the coated material is provided with a gluelayer and, during production of the frame, is fastened to it.

Preferred variants of the aeration and deaeration element are describedwith reference to the accompanying figures.

In the figures:

An aeration and deaeration element 1 is shown in FIG. 1, whose frame 10has the shape of a screw with an axial through-hole 11. The through-hole11 is covered by the coated material 13 in the region of screw head 12.The coated material 13 preferably consists in this variant of asubstrate in the form of a membrane 15, for example, from ePTFE, or alaminate from a layer of membrane 15 and a layer of textile woven fabric16 (see FIG. 3). This substrate is covered with the coating materialaccording to the invention. The aeration and deaeration element can beeasily screwed into a recess, for example, a hole, in a housing with thethreading 14 provided on the outside of frame 10.

The position of the coated material in the frame can be arrangedaccording to the application and manufacturing process on the upper endof the screw head 12 or at a certain depth of the throughhole 11.Another variant of the aeration and deaeration element 1 is shown inFIG. 2, in which a cover 20 is provided, in addition to the variantdescribed in FIG. 1. This cover 20 is connected by external force tosleeve 10 via fastening elements 21; for example, claws, which arearranged at a spacing around the periphery of the screw head. A spacing,through which air intake and removal can occur, is provided between theupper end of sleeve 10 and the lower end of cover 20.

The aeration and deaeration element according to the invention hasexcellent and thermal stability because of the properties of theemployed coated material, in which the coated material possessesoleophobism, even at high temperatures. The aeration and deaerationelement according to the invention can thus be used as a pressureequalization element for closure caps, in which emergence of liquidsfrom the container is avoided and sufficient aeration and deaeration ofthe container is simultaneously guaranteed.

Oil Repellency

The oil value is determined according to AATCC 118-1983 (AmericanNational Standard).

In this case, drops of 8 defined liquids with defined surface tensions(diminishing from liquid 1 to 8) are applied at room temperature to thesurface.

The oil value determination occurs by determining which liquid (1-8)does not is wet the surface or structure within 30 seconds. The higherthe liquid number (oil value), the higher the oil repellency(oleophobism).

A film of material can be produced to measure the oil value of thecoating material by coating an aluminum foil and etching the aluminumwith a dilute acid after heat curing of the layer, in order to obtain afilm of material. In the case of nonporous surfaces, unwetted is definedby the fact that the advancing wetting angle for the correspondingliquid is ≧50°.

Permeability

The apparatus of Coulter Electronics Limited, Luton, England, typePorometer II was used to determine permeability. The penetrating airamount in liters per minute and cm² is determined at a defined pressure(1 bar).

Wetting Angle

A goniometer microscope (Kruss GmbH, Hamburg, type G40) is used tomeasure the wetting angle. The wetting angle of a drop applied to thecoated surface is optically measured at room temperature.

Pore Size Determination

The apparatus of Coulter Electronics Limited, Luton, England, typePorometer II was used to determine pore size. The apparatusautomatically measures pore size distribution in porous materials bydefined driving off of liquids, described in ASTM Standard F3 16-86(American National Standard). The nominal pore size is the average poresize.

The invention will be further explained below with reference toexamples. It goes without saying that all other coating components andsubstrates corresponding to the instructions of the invention are alsoapplicable.

EXAMPLES

Examples 1 and 2 describe the synthesis of the coating materialaccording to the invention, coating of a substrate with such a coatingmaterial and the properties of the coated substrate. Both coatedsubstrates have an oil value of 7.

Examples 3 and 4 describe coated materials according to the invention,in which laminates are used as substrate. In Comparative Example 1,alkoxides with perfluorinated n-alkanes were used, according to theinstructions of EP-PS 0 587 557, instead of the perfluoropolyethersfunctionalized with a hydrolyzable group according to the invention. Anoil value of only 2 could be achieved with this coating on the samesubstrate as used in Examples 1 and 2.

For Comparative Example 2 an alkoxy-functionalized perfluoropolyether,as disclosed in JP-OS 4-213384, or also in most of the examples of WO97/01508, was hydrolyzed and used as only component in the coatingmaterial. Here again, an oil value of only 2 was obtained. This showsthat the desired high oil values can be achieved only when twocomponents are used. In Comparative Example 3, two components(tetraethoxysilane and C₈F₁₃CH₂CH₂Si(OC₂H₅)₃ were used, in principle,corresponding to the instructions of Example 4 of WO 97/01508, toproduce the coating. Here again, an oil value of only 2 could beachieved. This again shows that not only the use of at least twocomponents is absolutely essential, but also the specific choice ofcomponents according to the invention, in order to achieve higholeophobism. In this example fluorinated solvents were used according tothe instructions of WO 97/101508.

Comparative Example 4 corresponds, in principle, to Comparative Example3, except that, in this case, a mixture of water and isopropanol wasused as solvent, as is described as advantageous in the presentinvention. An oil value of only 2 was also achieved in this case.

EXAMPLE 1

4 g hydrochloric acid (37%) is added during vigorous agitation to amixture of 357 g methyltriethoxysilane (Huls), 113 g tetraethoxysilane(Hüls) and 200 g silica sol (Bayer Levasil 300/30 [30% SiO₂ in water]).The reaction mixture cools off within 2 hours and 1348 g isopropanol isadded during agitation. After 14 hours of agitation, 89 g isopropanoland 11.25 g perfluoropolyetherfunctionalized triethoxysilane are addedto 100 g of the aforementioned mixture (mixture A).

(CF₃[OCF(CF₃)CF₂]_(d)(OCF₂) _(e)OCONHCH₂CH₂CH₂Si(OC₂H₅)₃, molecularweight 800-900; MF407 from Ausimont).

The coating material is applied by the roll coating technique (coatingin the gap between two rolls filled with the coating material) to amicroporous polymer membrane described in U.S. Pat. No. 4,194,041(nominal pore size 0.2 μm, thickness 0.03 mm). The application amount isessentially obtained by the solids content (here 11%) and by the gapadjustments and pressures of the rolls.

At the end of the coating step, the membrane is treated in a continuousfurnace at 150° C. and a residence time of the coated material of 1.5minutes to evaporate the solvent and for thermal curing of the coating.

The application amount referred to solids is determined by differenceweighing at 4.4 g/m².

The oil value on both sides is 7. After holding of the membrane at 160°C. for 12 hours, at 200° C. for 2 hours and at 250° C. for 2 hours, theoil value is determined. In all measurements, the oil value is unchangedat 7. The permeability of the coated membrane is 4.8 L/min per cm².After application of a drop of ATF oil to the coated surface andsubsequent holding at 160° C. for 12 hours, the wetting angle of thedrop is >10°.

EXAMPLE 2

85 g of MF407 is added during agitation to a mixture of 22.6 gtetraethoxysilane and 20 g isopropanol. 6.3 g of 0.1 M HCl is then addedand agitated overnight. The material is diluted in a 1:4 ratio (parts byweight) with isopropanol for coating.

The subsequent process is similar to Example 1. The uncoated membranethen has a permeability of 4.4 L/min per cm².

The application amount referred to solids is determined at 6.8 g/m².

The oil value is 7 on both sides. The permeability of the coatedmembrane is 3.0 L/min per cm².

After application of a drop of ATF oil to the coated surface andsubsequent holding at 160° C. for 12 hours, the wetting angle of thedrop is >10°.

EXAMPLE 3

Coating material, coating technique and curing similar to Example 1. Alaminate (basis weight 95±10 g/m², thickness 0.1 mm) made of ePTFE,described in U.S. Pat. No. 4,194,041 (nominal pore size 0.5 μm), and anylon taffeta textile is used as substrate.

The application amount referred to solids is determined by differenceweighing at 5 g/m².

The oil value is 7 on both the ePTFE and nylon taffeta surface. Thepermeability of the coated membrane is 0.6 L/min per cm² at a pressureof 0.1 bar and is therefore unchanged in comparison with the uncoatedlaminate.

After application of a drop of ATF oil to the coated ePTFE surface andsubsequent holding at 160° C. for 12 hours, the oil does not penetratethe porous structure, i.e., the wetting angle of the drop is >10°.

EXAMPLE 4

Coating material, coating technique and curing are similar to Example 1.A laminate (basis weight 99±10 g/m², thickness 0.1 mm) from ePTFE,described in U.S. Pat. No. 4,194,041 (nominal pore size 0.9 μm), and apolyester textile (nonwoven) are used as substrate.

The oil value is 6-7 on both the ePTFE and polyester surface. Thepermeability of the coated membrane is 1.7 L/min per cm² at a pressureof 0.1 bar and is therefore changed no more than 20% relative to theuncoated substrate. After application of drop of ATF oil to the coatedePTFE surface and subsequent holding at 160° C. for 12 hours, the oildoes not penetrate the porous structure; i.e., the wetting angle of thedrop is >10°.

Comparative Example 1

The procedure of Example 1 is followed, but 14 g of C₆F₁₃CH₂CH₂Si(OC₂H₅)(ABCR Company), as well as 188 g isopropanol, are added to 100 g ofmixture A instead of MF407.

The rest of the procedure is similar to Example 1. The uncoated membranehas a permeability of 4.4 L/min per cm².

The application amount referred to solids is determined at 2 g/min².

The oil value on both sides is 2. The permeability of the coatedmembrane is 3 L/min per cm².

Comparative Example 2

15 g MF407 is diluted with 185 g isopropanol and mixed during agitationwith 0.95 g 0.1 M HCl and agitated overnight.

The rest of the procedure is similar to Example 1. The uncoated membranehas a permeability of 4.2 L/min per cm².

The application amount referred to solids is determined at 2 g/min².

The oil value is 2 on both sides. The permeability of the coatedmembrane is 3.0 L/min per cm².

Comparative Example 3

5 g tetraethoxysilane, 5 g C₆F₁₃CH₂CH₂Si(OC₂H₅)₃ and 50 g FC 75(perfluoronaphthyl tetrahydrofuran, available under the tradenameFluorinert FC 75, PCR_(p) Inc., Gainesville, Fla.) are mixed and addedduring agitation to 14.9 g hifluoroacetic acid and agitated for 3 hours.

75.9 g of FC 75 is then added and ePTFE is then coated by roll coatingin similar fashion to Example 1. Curing occurs for 30 minutes at 150° C.The oil value is 2. The application amount is 10 g/m² The permeabilityis determined at 1.2 L/min per cm².

Comparative Example 4

208.8 g tetraethoxysilane and 200 g isopropanol are mixed duringagitation with 27 g 0.1 N HCl. After 17 hours of agitation, 12.5 g ofC₆F₁₃CH₂ CH₂Si(OC₂H₅)₃ and 75 g isopropanol are added to 10 g of thereaction mixture. ePTFE is then coated by roll coating in similarfashion to Example 1. Curing occurs for 30 minutes at 140° C. The oilvalue is 2. The application amount is 3.5 g/m². The permeability isdetermined at 3.7 L/min per cm².

What is claimed is:
 1. Coated material, comprising: a porouspolymer-substrate and a coating material applied to at least one surfaceof the substrate, which material comprises condensates of at least onecompound A of the general formula R_(a)MZ_(b) (a=0-3; b=1-4; a+b=3-4),in which R is a nonhydrolyzable organic group, and at least one compoundB of the general formula R′_(x)MZ_(y) (x=1-3; y=1-3; x+y=3-4), in whichR′ is a nonhydrolyzable organic group, and at least one R′ contains aperfluoropolyether structure separated from M by at least two atoms, inwhich M is an element chosen from groups IIIA-VA or groups IIB-IVB ofthe periodic system and Z is a hydrolyzable organic group, and in whichat least one R is not identical to at least one R′.
 2. Coated materialaccording to claim 1, in which the polymer is chosen from a groupconsisting of at least one fluoropolymer.
 3. Coated material accordingto claim 2, in which the polymer is expanded polytetrafluoroethylene(ePTFE).
 4. Coated material according to claim 1, in which the substrateis present in the form of a membrane, a sealant or textile fabric. 5.Coated material according to claims 1, in which the substrate is presentin the form of laminate, consisting of at least one layer of a membraneand at least one layer of a textile fabric.
 6. Coated material accordingto claim 1, in which the substrate is a membrane bonded to a textilefabric.
 7. Coated material according to claim 1 with an oil value ≧3. 8.Coated material according to claim 1 with an oil value ≧5.
 9. Coatedmaterial according to claim 1 with an oil value ≧7.
 10. Coated materialaccording to claims 1, in which the oil value of the coated substrateremains unchanged after heat treatment at 160° C. for 12 hours. 11.Coated material according to claim 1, in which the oil value of thecoated substrate remains unchanged after heat treatment at 200° C. for 2hours.
 12. Coated material according to claim 1, in which the oil valueof the coated substrate remains unchanged after heat treatment at 250°C. for 2 hours.
 13. Coated material according to claim 1, in which thewetting angle of a drop of transmission fluid (ATF oil) on the coatingis >10° after heat treatment at 160° C. for 12 hours.
 14. Process forproduction of a coating material that comprises mixing of at least onecompound A of general formula R_(a)MZ_(b) (a=0-3; b=1-4; a+b=3-4), inwhich R is a nonhydrolyzable organic group, and at least one compound Bof the formulaCF₃[OCF(CF₃)CF₂]_(d)(COCF₂]_(d)(OCF₂)_(e)OCONHCH₂CH₂CH₂Si(OR)₃ (d and e≧0, and d=1-10), in which M is an element chosen from groups IIIA-VA orgroups IIB-IVB of the periodic system and Z is OR″ in which R″ is anorganic group.
 15. Coating material, which comprises a condensate of atleast one compound A of general formula R_(a)MZ_(b) (a=0-3, b=1-4;a+b=3-4), in which R is a nonhydrolyzable organic group, and at leastone compound B of the formulaCF₃[(OCF(CF₃)CF₂]_(d)(OCF₂)_(e)OCONHCH₂CH₂CH₂Si(OR)₃ (d and e ≧0, andd=1-10), in which M is an element chosen from groups IIIA-VA or groupsIIB-IVB of the periodic system and z is OR″ in which R″ is an organicgroup.
 16. Aeration and deaeration element characterized by a framepossessing at least one air inlet and outlet opening, the air inlet andoutlet opening being covered by a coating comprising a substrate and acoating material applied to at least one surface of the substrate, inwhich the coating material comprises condensates of at least onecompound A of general formula R_(a)MZ_(b) (a=0-3; b=1-4; a+b=3-4), inwhich R is a nonhydrolyzable organic group, and at least one compound Bof the general formula R′_(x)MZ_(y) (x=1-3; y=1-3; x+y=3-4), in which R′is a nonhydrolyzable organic group, and at least one R′ contains aperfluoropolyether structure separated from M by at least two atoms, inwhich M is an element chosen from groups IIIA-VA or groups IIB-IVB ofthe periodic system and Z is a hydrolyzable organic group, and in whichat least one R is not identical to at least one R′.
 17. Aeration anddeaeration element according to claim 16, characterized by the fact thatthe substrate is porous polymer.